Anterior Cruciate Ligament (ACL) injury afflicts at least 200,000 young Americans annually. At least, 50 percent of individuals develop Osteoarthritis (OA) in the ten years after the injury and this imposes a substantial burden on the U.S. health care system. The gold standard for treating the ACL-injured individual is unknown, despite the vast array of surgical and treatment options available. No standard, sensitive, and reliable method exists to compare biomechanical effectiveness of current treatments. Moreover, the lack of such instruments leaves clinicians unable to identify the complicated changes in 3D motion patterns and particular contact mechanics that occur with ACL injury, which play an important role in onset and progression of OA. Our new biomechanical assessment platform that integrates computational modeling and 3D measurements of joint function in the clinical setting will shift research and clinical practice paradigms. It will bridge the gap between clinical and laboratory methods of assessing joint function, thereby overcoming the disadvantage of each. A symbolic computational approach that generates the full nonlinear model equations in a smooth, explicit form allows application of powerful tools from modern control theory and efficient, real-time implementation. Our integrated experimental and controls framework allows implementation of novel theoretical concepts into the real-time clinical setting that will vertically advance treatment of ACL injury. The developed device could ultimately be used as a tool for evaluation, treatment planning, objective assessment, comparison, and monitoring of the knee after any musculoskeletal injury or treatment. The instrument has high commercial value due to its broad capabilities and applications and can easily be sold or licensed to hospitals or rehabilitation centers. PUBLIC HEALTH RELEVANCE: Anterior Cruciate Ligament (ACL) injury afflicts at least 200,000 young Americans annually. At least, 50 percent of individuals develop Osteoarthritis (OA) in the ten years after the injury and this imposes a substantial burden on the U.S. health care system. The proposed robotic device will use as a clinician tool for evaluation, treatment planning, objective assessment, comparison, and monitoring of the knee after any musculoskeletal injury or treatment significantly lowering patient discomfort and overall cost burden to the system.